Various types of apparatus as well as varying methods are used in the processing and conditioning of yarn and similar elements such as are disclosed in the following United States patents:
U.S. Pat. No. 4,414,756 PA1 U.S. Pat. No. 4,316,370 PA1 U.S. Pat. No. 3,972,176 PA1 U.S. Pat. No. 3,774,384 PA1 U.S. Pat. No. 3,696,601 PA1 U.S. Pat. No. 3,632,092